Jet-powered lifting rotor for rotary wing aircraft



Jan. 4, 1949. STALKER 2,457,936

JET-POWERED LIFTIHG ROTOR FOR ROTARY WING AIRCRAFT Filed larch 21, 1945 2 Sheets-Sheet 1 r 1111/1111 A r J q- IL 29 L co 2.

a) In, Za la 2 A 3| a Z O 32. a; "E 'T 7 INVENTOR E. A. STALKER 2,457,936

JET-POWERED LIFTING ROTOR FOR ROTARY WING AIRCRAFT Jan. 4, 1949.

2 Sheets-Sheet 2 Filed March 21. 1945 INVENTOR Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE JET-POWERED LIFTING ROTOR FOR ROTARY WING AIRCRAFT Edward A. Stalker, Bay City, Mich. Application March 21, 1945, Serial No. 583,919

8 Claims. 1

My invention relates to aircraft and particu-.

larly to rotary wing aircraft.

An object of the invention is to provide a means of increasing the power for rotating the lifting rotor by jet action. 1

Another object is to provide an eflicient means of burning fuel in the interior of the outer extremity of the blade so that an increase in propulsive thrust may be obtained.

It is also an object of the invention to provide a means of burning the fuel intermittently or only during a specific portion of the blade orbit.

Still another object is to provide means of synchronizing the burning of fuel with a means of increasing the jet opening area. Other objects will appear from the description, drawings and claims.

I accomplish the above objects by the means illustrated in the accompanying drawings in which- Figure 1 is a side elevation of a helicopter;

Figure 2 is a fragmentary top plan of a blade;

Figure 3 is a section along the line 3-3 in Figure 2;

Figure 4 is a fragmentary plan of the mechanism to operate the auxiliary flap;

Figure 5 is a fragmentary elevation of the hub part of the mechanism of Figure 4;

Figure 6 is a fragmentary vertical section H of Figure 2 showing the manner in which the blade root forks are fastened to the hub;

Figure "l is a fragmentary section along the line 1-1 of Figure 6 and shows the fuel metering valve mechanism along with the circuit breaker of the jet slot opening mechanism;

Figure 8 is a fragmentary diagram of the fuel quantity compensator and the fuel injection nozzle;

Figure 9 is a fragmentary section along the line 9-4 of Figure 2 showing the auxiliary mech. anism for increasing the slot opening for the hot air jet; and

Figure 10 is a atic scheme of the electric circuit for the control of combustion and the jet slot area.

In my application Serial No. 553,082, filed September '7, 1944, of which the present application is in part a continuation. I disclosed means of equipping a rotor blade with a slot and asuitable flap to control the slot area as a function of the orbital position of the blade. A propulsive-,-

jet of fluid is emitted through the slot. The blade also had a lift flap for altering the lift automatic'ally as a function of the orbital position of the blade.

In the present case I provide means to burn fuel in the air within the blade and means to adjust the slot area to emit the less dense fluid of the heated jet while still retaining the control of the slot area orbitally. If the area werenot increased the mass of fluid discharged per second could not increase satisfactorily because of the lower density. 0n the other hand if the slot area were corrected for the heated air it would be incorrect for the cold air and would cause losses.

The mechanism for controlling the slot area by the flap at the slot exit will first be described although this is not the subject of the claims in this application. It is necessary however for the understanding of the features of the invention of the present case.

The helicopter of Figure 1 has the rotor blade I supported from the hub 2 and free to flap ver-' tically about the axis 20. The blade is equipped with the main flap 3 and the auxiliary flap 4. Each blade is attached by the fork in to the hub to be revolved about a vertical axis. As shown in Figure 3 the main flap has an upper contour of radius R so that rotation of the main flap about the hinge at the origin of the radius does not vary the slot between the auxiliary flap 4 and flap 3.

The rotor is revolved by a jet of air emitted from the passage or duct 5 through the slot 6 rearward along the surface of the,fiap. This type of propulsion has been described in more detail in my U. S. Patent No. 2,084,464. Air is forced into the hub by power means and flows to the slot via the duct 5 formed by the blade walls.

The helicopter can be propelled more emciently by discharging most of the jet from the advancing blade than by discharging it equally about the orbit. The emciency of propulsion is a function of the ratio of jet speed V; to blade speed Va as indicated by the following equation aseasse The auxiliary flap t which is hinged at 8 is raised on the advancing blade to increase the opening of the slot and it is lowered on the retreating side to decrease the slot opening. The slot width should be varied rapidly when the blade is near the front and back positions. This is accomplished by the variable displacement means incorporating the cam plate It! whose cam groove accommodates the end of arm i attached to the flap 4. The camplate is slideable on the rollers II and when such motion takes place the arm 1 is moved to rotate the auxiliary flap.

The motion of the cam plate I0 is referred to the orbital position of the blade about the upright axis by means of the cam I2 and suitable mechanism connecting it to the cam plate.

Cam I2 is attached rigidly to shaft I3 which is in turn fixed rigidly to the aircraft structure. Plate I4 is part of the hub to which the helicopter blades I are attached and is free to rotate on bearings i5. Fork I6 which is part of plate I4 supports fork I! on the axis I8. Fork I1 is an integral part of arm I9 which is caused to oscillate around axis I8 by roller 20 riding in the slot of cam I2. Fork 2I is pinned to nut block 22 at one end and at the other to slide rod 22a which slides in sleeve 2212 supported on arm 220 which is part of plate I4. Slide rod 22a actuates flexible push-pull cable 23 which transmits spanwise motion to slide rod 23a and in turn moves cam plate I0. Slide rod 23a is supported by sleeve 24 which is fastened to the blade structure. The blade-I is free to swing vertically around horizontal hinge 2a which causes sleeve 24 and slide rod 23a to move up and down relative to slide rod 22a. Flexible push-pull cable 23 permits this relative vertical motion without affecting the spanwise positions of either slide rod 22a or 23a. Rollers II, supported by the blade structure, allow cam I0 to slide spanwise. Link 25 connects a plurality of cams identical to In distributed along the span. Nut block 22 can be moved so that axis 25 can be moved from position A to position B by revolving screw 21. Screw 21 is turned by pinion 28 mating with rack 29. Universal joint 30 fastened to rack 29 lies on axis I8 so that oscillation of arm I9 will not affect the vertical position of rack 29. Link 3| is moved by arm 32 which is pivotally supported by fork 33. They revolve with hub I4 around shaft I3. Grooved sleeve 34 does not revolve on shaft I3 but is ,free to slide vertically by the action of bellcrank 35 and link 36. The last is attached able by the pilot.

For forward flight, nut block 22 remains fixed at the outer end of crank I9 and oscillates between positions A and Cby the action of roller 20in cam I2. Cam I0 is thereby caused to reciprocate moving roller 9 and arm 1 causing flap 4 to move from position D to F and back.

As the rotor blade revolves around its orbit from G to H (see Fig. 4. of which direction GK is forward) the flap 4 opens from F to D (see 0 a control oper- Fig. 3). As the blade revolves from H to I to J the flap 4 remains wide open. Revolving from J to K the flap 4 closes down again to F and remains there while theblade revolves to L and then to G.

In hovering flight nut block 22 is moved from position A to B with the crew 21. Position B is on axis I8, therefore the oscillation of crank arm I9 imparts no motion to link 2|. The geometry of point B relative to A and C is such that cam 4. ill is held at an intermediate position putting flap =3 into fixed position E.

The lift flap 3 is controlled orbitally by a suitable mechanism as connected to the universally mounted ring 55d whose tilting by the pilot by means of rod 56 determines the attitude of the flap for various blade positions in its orbit. Since this mechanism is not a feature of this invention it will not be further described. A detailed description is given in my application Serial No. 553,082, filed September 7, 1944.

The lifting rotor composed of blades l is normally rotated by means of the jet issuing from slot 6 as a relatively cold jet. Under special conditions such as climbing or when very high forward speed is desired, fuel is to be burned in a portion of the air flowing in the blade to increase the jet velocity and thereby the propulsive power driving the blades.

' The blade interior is divided into a plurality of spanwise ducts by partitions 85, 81, 88 and 89 having portions of the slot 6 as their exits. Into some of these ducts fuel is injected and burned.

The flap 4 is divided into two parts, an inner one 4b for the control of the slot area for the relatively cold jet, and an outer one 4a for the control of the hot jet. The control of the movement of the outer portion of the flap 4a in relation'to the combustion of fuel is altered from the general motion provided by the cam I0 as previously described. When the outer jet is not hot the mechanism reverts to the same type of control as for the cold jet of the inner portion of the slot.

The fuel metering mechanism is shown in Figure 7. The cam 90 is fixed toand rotates with the hubcylinder 59. The roller 92 is attached to the central slide rod 94 and is held against the cam by the spring 96. The slide rod 94 rides 4" inside the tube 98 the position of which is controlled by the pilot by means of rod 99, and this tube in turn rides inside the valve cylinder I 00 which is fixed to the fuselage. With the rotation of the cam plate 90 the central slide rod 94 oscillates at a frequency proportional to the rotor speed and with a constant stroke. By adjusting the tube 98 the length of time during which the rod slot I02 and the tube slots I04 register with each other can be varied. The fuel is fed to the valve by a constant pressure pump and enters through the opening v I06, passing through the valve during the time the slots register and leaving through the fuel line I08. The

the slip valve I I2 mounted on the stationary shaft l3. The slot I I4 permits fuel to be fed only to the advancing blade since only one fuel line passes by the slot .I I4 at any instant.

Before the fuel. reaches the injection nozzles within the blade it passes a needle valve I I6 which compensates for the temperature and mass flow of the air in the duct, thus maintaining a proper fuel-air mixture. Within the blade the venturi I I8 attached to the Sylphon I20 corrects for mass flow variations of the duct air and the sealed Sylphon I22 corrects for the duct air temperature.

. See Figures 2 and 8. The two Sylphons are concrank arm I20. This screws the needle up or down and changes the metering of the fuel.

The nozzles I30 through which the fuel is injected contain a spring-loaded needle valve I32 amas from the nozzle opening by extending the flexible seal I and compressing the spring I.

disintegrates the fuel into very minute particles that mix readily with the passing air. 1

In the plan view of the blade, Figure 2, the arrangement of the injection nomies I" and the ignition spark plugs I42 is shown. Fuel is burned only in theouter portion of the blade and the air feeding that portion ofthe blade is separated from the inboard air by the partition I5. There are four sets of the fuel nozzles and spark plugs, each located in a separate duct and at an equal distance from the jet slot 8 so that the hot'air will be jetted evenly along the full length of the portion of the slot emitting hot air.

Since the hot jet occurs only at the outer half of the slot it is necessary, to divide the jet flap 4 into two parts la and 4b so that the opening The. due jet of fuel strikes the dash plate Ill which.

. I x 8 breaker which provides a means of increasing the Jet slot area in cooperation with the fuel injection.

It willnow be clear that I have provided a unique means of burning fuel in the blade to augment the power available for climbing and high burning coincides with the advancing position ofx the blade.

through whichthe hot air passes can be wider same mechanism as shown in Figure 3 during the time in which the cold air jet is in effect. Additional jet opening is obtained by means of a set of solenoids which vary the action of the primary mechanism employing the cam plates II. The arm I in this instance is hinged at the flap hinge l but is free from the flap la. The link III connects the flap to the solenoid arm in which hinges about the point I" on the arm I" fixed to the main flap arm I. The arm In is essentially the core of the solenoid I" and its movement is restricted by the poles of a second U- shaped solenoid I" fixed to the flap arm I. .When the solenoid circuit is closed, the arm I" is drawn forward and held against the lower pole of solenoid I" thus causing the flap 4 to decrease the jet opening to normal. When the hot gases are passing through the slot, the solenoid circuit is broken thus permitting the internal pressure to open the slot to its maximum width as shown in Figure 9.

Thecircuit breaker controlling the solenoids is shown in Figure 7. The circuit is opened and closed by a sliding contactor I62 which is attached to and moves with the slide rod 94, Fig. 7. The circuit is open as shown in Figure"! and will be closed when the contactor I82 lies between thetwo contactor plates I. These plates are housed in a cylinder I" the position of which, relative to the stroke of the sliding contactor, can be regulated by the pilot by means of rod I01 so that the period of time during which the Jet slot is wide open will produce the most effective and emcient jet action.

Since the fuel is burned only during a portion of the advancing side of the orbit it is desired that only the advancing blade flap circuit be broken. This is achieved by means of a split slip ring I" mounted on the stationary shaft I3. The electrical circuit is shown in Figure 10. The brushes I'll contact the slip ring and complete the circuits within the blades. The half of the slip ring on the retreating side is connected directly to the electric power source I" and therefore the closed circuit holds the jet slot to the normal width. The advancing side of the slip ring I have also provided a unique means of controlling the cross sectional area of the jet at exit which makes added power and high emciency available.

I have now described suitable embodiments of my invention which are now preferred. It is to be understood however that the invention is not limited to the particular construction illustrated and described and that I intend to claim it broadl? as indicated by the scope of the appended claims.

I claim:

1. In combination in a rotary wing aircraft, a-

hollow blade, means supporting said blade for rotation about an upright axis, said blade having a spanwise slot in its surface adapted to discharge a gaseous flow therethrough, a partition. within said bladedividing the interior thereof into a plurality of ducts each having a portion of said slot as an exit, means to cause combustion in a said duct to raise the temperature of said air therein, and flap means on said blade associated with said duct in which combustion has taken place to provide increased flow area to accommodate the I wise slot in its surface leading out of the blade interior and adapted to discharge a gaseous flow therefrom, means to heat a portion of said air being emitted from a portion of said slot, and flap means on said blade associated with said slot and adjustable differentially to provide increased flow area in that portion of the slot through which the heated portion of the air is emitted.

3. In combination in a rotary wing aircraft, a blade having a spanwise passage for the flow of air therethrough, means supporting said blade for rotation about an upright axis, said blade having a spanwise flap adjustably supported'thereon to form a slot between the wing surface and said flap surface adapted to discharge a gaseous flow therefrom, means to periodically heat said air from, means to cause periodic combustion in said air within said blade to increase the air temperature, and means to vary the size of said opening in timed relation to said combustion periods.

5. In combination in a rotary wing aircraft, a

blade having a slot of variable area leading out of a the blade interior adapted to discharge a gaseous flow therefrom, means supporting said blade for rotation about an upright axis, controllable has between it and the power source the circuit means .to inject fuel into said air within said 7 blade, means to ignite said fuel, and means onerable in accordance with the orbital position of said blade to coincidentally control the said slot area and the injection of said fuel.

6. In combination in a rotary wing'aircraft, a blade having a slot of variable area leading out of the blade interior and adapted to discharge a gaseous flow therefrom, means supporting said blade for rotation about an upright axis, controllable means to intermittently inject fuel into said air within said blade, means to ignite said fuel, means to vary said slot area, and means operable coincidentally with the operation of said fuel injection means for controlling said slot varying means to increase said slot area intermittently with said injection of fuel.

'7. In combination in a rotary wing aircraft, a blade main body and a flap supported thereon,

I said flap and said main body forming a slot therebetween leading out of the blade interior adapted to discharge a gaseous flow therefrom, a plurality of auxiliary flaps supported on said blade to control said slot area, means to cause combustion in a part of said air within said blade, and means to control said auxiliary flaps to provide increased flow area to accommodate the greater volume of flow of the heated air discharged therethrough f ollowlng combustion therein.

8. In combination in a rotary wing aircraft, a blade having a slot leading out of the blade interior adapted ,to discharge a gaseous'flow therefrom, means supporting said blade for rotation about an upright axis,means'to initiate. combustion in said air within said blade, and means to increase said slot area upon initiation of said combustion.

r EDWARD A. STAIKER.

REFERENCES The following references areof record in the file of this patent:

UNITED STATES PATENTS 

